Interpersonal violence is a leading cause of morbidity and mortality amongst adolescents and is likely the end result of a complex interplay between individual, family, and environmental factors that are often dynamic across the adolescent years. Most research to date has focused on risk factors for violence perpetration and less is known about factors that protect youth from violence. Adult connection plays a crucial role in adolescent development and may play a role in limiting violence perpetration and victimization. However, research examining the association between adult connection and violent victimization is limited, often includes a limited age range, and has traditionally relied on self-report measures. Also, the effect of the environment on youth violence is poorly understood due to sparse and conflicting data. In response to this need, we propose to analyze data from an innovative population-based case control study (R01AA014944) that mapped the travel paths of adolescents' daily activities to identify risk factors for assault injury. Using this unique opportunity and novel methods we will more accurately measure the nature and strength of adult connection and neighborhood exposure in order to address the following specific aims: 1) To assess whether presence of adult connection is associated with decreased odds of violent assault injury in adolescent males; 2) To assess whether adolescent characterizations of connections (e.g. supportive vs. unsupportive) with adult family members are associated with decreased odds of violent assault injury in adolescent males, and determine which family connections are most salient; and 3) To assess whether adult connection is associated with differential exposure to neighborhood risk and protective factors over the course of daily activities. Through this analysis, the applicant will develop a deeper understanding of the association between adult connection and odds of assault injury, understand how the association may differ as adolescent- adult relationships change across development, examine the mechanisms through which adult connection may lead to decreased violence exposure, and identify opportunities to bolster adult connection and protect youth. This work is closely aligned with NIH, CDC and Healthy People 2020 priorities. The proposed research project will be in the context of the applicant completing requirements for a PhD in Clinical Epidemiology. The degree program will encompass intensive instruction in the fundamentals of epidemiology, biostatistics, study design, data management, and analytic methods, which will enhance and guide the research process of the applicant. The grant funding will enable additional multifaceted training and career development with complementary mentors with expertise in youth violence, spatial epidemiology, adolescent development, adolescent-adult relationships, community-based interventions, and translational research. The longer-term objectives of the applicant for this grant are to analyze the data, prepare manuscripts for publication, and use the results as a foundation for a future K award application.